Easy-access beverage pouch

ABSTRACT

The invention relates to pouch or bag-shaped beverage containers (1) having an opening system which is pierced by a straw to access the beverage. The container includes a wall (14) which is a multilayer laminate which from the outside to the inside includes polyester film (3), printing ink (4), adhesive (5), foil (6), adhesive (7) and polyethylene film (8). In order to facilitate piercing of wall (14) by a straw, a portion of the outer polyester film is removed at an area (2) which is intended to be pierced by a straw as is known in the art. To further facilitate piercing of wall (14) an area of delamination (9) is created opposite area (2) between foil layer (6) and the polyethylene film (8). Area of delamination (9) is created by vaporizing adhesive layer (7) by means of laser radiant energy which is transmitted through the polyethylene film (8) and absorbed by adhesive layer (7).

This application claims benefit of U.S. Provisional Application No.60/019,096, filed Jun. 3, 1996.

FIELD OF THE INVENTION

The present invention relates generally to beverage containers whichhave an opening through which the beverage is consumed by means of astraw, and more particularly to a pouch or bag-shaped beverage containerhaving an opening system which is pierced by a straw to access thebeverage.

BACKGROUND OF THE INVENTION

In pouch or bag-shaped beverage containers having a membrane seal whichis to be pierced by a straw, there is a problem making the sealsufficiently easy for the consumer to pierce. The piercing of themembrane seal may especially be a problem for small children whofrequently utilize such containers and who lack the dexterity of adults.

The beverage pouches which are currently being marketed are fabricatedfrom a laminated sheet material which is built up as follows from theoutside to the inside: polyester film/printing ink/coatingadhesive/metal foil/coating adhesive/heat-sealable plastic (e.g.,polyethylene) film. Such a laminate is further described in U.S. Pat.No. 5,425,583 which is hereby incorporated by reference.

In the present commercial pouches, the outer polyester foil is removedwithin a straw piercing area so that the straw (typically a pointedstraw) does not have to pierce the polyester film. Typically the strawpiercing area is in the shape of a circle having a diameter in excess ofthe diameter of the straw. The straw piercing area has usually beenremoved from the polyester film before this film is laminated or adheredto the metal foil. To gain access to the pouch the straw must then onlypierce the metal foil and adhered polyethylene film; however, this hasstill proven to be a difficult task.

Aforementioned U.S. Pat. No. 5,425,583 discloses an improved strawpiercing opening wherein a hole is punched through all layers of thepouch laminate and a sealing film is affixed to the inner side of thepolyethylene film around the straw piercing opening. Although thisapproach facilitates entry of the straw into the pouch, the addedmaterial and operational cost associated with this approach are notdesirable.

SUMMARY OF THE INVENTION

According to the present invention, access to a pouch by a straw isfacilitated by the application of laser energy to the inside surface ofthe laminate such that, within the straw piercing area, one or moreareas of delamination are created between the inner polyethylene layerand the metal foil. If the pouch laminate contains an outer polyesterfilm, the polyester film is preferably removed in the straw piercingarea. This removal may be done, as in the prior art, by punching out astraw piercing area from the polyester film before this film is adheredto the metal foil; alternatively, the polyester film may be removed fromthe straw piercing area by laser treatment after the polyester film hasbeen adhered to the metal foil.

The pouch laminate described in U.S. Pat. No. 5,425,583, which isexemplified by the sheet material used to fabricate CAPRI SUN® beveragepouches, typically uses polyethylene terephthalate as the polyester filmand aluminum as the metal foil. The heat-sealable plastic film, may beany ethylene homopolymer or copolymer. The adhesive layers are generallypolylefin-based, interlaminar bonding agents known for use as bondinglayers in laminated structures. The composition and fabrication of thesebeverage pouch laminates are known in the art.

In order to effect delamination between the inner heat sealable plasticlayer and the metal foil, laser energy is employed, whereby pulses oflight energy are directed, or focused onto the laminate. The innerheat-sealable plastic layer must have a relatively lower absorptioncoefficient for laser radiant energy such that a high percentage(preferably at least 90%) of the radiant energy passes through thislayer. In contrast the adhesive layer must have a relatively higherabsorption coefficient for laser radiant energy such that a highpercentage of the radiant energy is absorbed and transformed largelyinto heat. The adhesive layer may include such polymers as polyethyleneterephthalate, polyvinyl alcohol or polyvinyl chloride to obtain thedesired absorption coefficient. The laser energy is supplied in adesired pattern and with the appropriate intensity to cause localizedheating and melting and vaporization of the adhesive layer. Desirablythe generated heat also melts and vaporizes a portion of the plasticfilm layer adjacent the adhesive and promote crystallization of thepolymers within the remaining plastic film layer.

Delamination of the plastic film layer from the metal foil has beenfound to greatly facilitate piercing of the pouch laminate by a straw.Also facilitating rupturing of the laminate in the fact that the plasticfilm will become crystallized in the area where laser energy is appliedif sufficient heat is generated in these areas. Crystallization of theplastic film reduces the elongation and tensile strength of the filmwhich also enables easier rupturing of the film by a straw. Anyconfiguration or pattern of delamination within the straw piercing areamay prove to be suitable. Thus, delamination may be effected in a singleintegral area or in spaced-apart areas. These spaced-apart areas couldbe spots, straight lines or curved lines.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a beverage pouch.

FIG. 2 shows a cross-sectional view of the pouch laminate through thefront wall of the pouch along the view line II--II.

FIG. 3 shows an embodiment of areas of delamination within a circularstraw piercing area, as viewed from the inside of the pouch.

FIG. 4 shows an alternate, and preferred, embodiment of an integral areaof delamination within a rectangular straw piercing area, as viewed fromthe inside of the pouch.

BEST MODE OF THE INVENTION

With reference to the drawings, FIG. 1 illustrates a flexible pouch ofthe present invention generally indicated as 1 that includes flexiblefront and back wall panels 12 and 14, respectively, which aresuperimposed over one another and sealed together (e.g., heat-sealed)along side peripheral edges 16 and 17 to form side seals 18 and 19,respectively, and along top peripheral edge 20 to form top seal 21. Asis known in the art, as further described in U.S. Pat. No. 4,898,477which is hereby incorporated by reference, the bag may be completed bymeans of a bottom gusset panel 26 which is attached to the inner surfaceof wall panels 12 and 14. A circular straw piercing area is indicated at2, although this area may be formed in a variety of shapes.

FIG. 2 shows a longitudinal section through the front wall 14 at alocation which is slightly offset from the center of the straw piercingarea. Wall 14 consists of a laminate which is as follows from theoutside to the inside: polyester film 3 (about 12 microns)/printing ink4/coating adhesive 5/aluminum foil 6 (about 12 microns)/coating adhesive7/polyethylene film 8 (about 100 microns). Straw piercing area 2 isdepicted by the absence of layers 3, 4 and 5. An area of delamination 9(shown in cross-section) denotes the essential absence of adhesive layer7 along with removal of a portion of polyethylene film 8.

FIG. 3 shows a pattern of spaced-apart areas of delamination 9, depictedas darkened areas substantially within the circular footprint of strawpiercing area 2. These areas of delamination may be created by means oflaser coding apparatus, such as the dot matrix laser coding equipmentcommercially available from Lumonics Corporation, Oxnard, Calif. underthe XYMARK™ Sprint II brand name. This apparatus is able to convert aprimary laser beam into a plurality of individual beamlets which may befocused on a moving workpiece, such as web material, in order to producea desired pattern.

FIG. 4 depicts an arc shaped area of delamination 23 within thefootprint of a rectangular straw piercing area 22. This area ofdelamination 23 results from delivering an intense pulse of laser energyin the image of the shaded areas 24. LaserMark® carbon-dioxide lasermarking equipment systems, also available from Lumonics, is suitable forthis purpose and have been found to be preferred for use in thisinvention. According to LaserMark® systems, a pulsed beam of light froma laser is used to illuminate a mask, the image of the mask is thendemagnified onto the surface of the workpiece to produce the desiredpattern. The mask contains curvilinear cut-out areas in the shape ofshaded areas 24 and when laser energy impacts the laminate, adhesivelayer 7 is vaporized within shaded areas 24 and polyethylene film 8 iscrystallized within shaded areas 24. Due to the amount of heat generatedby the laser, adhesive layer 7 will also melt within unshaded areas 25resulting in essentially complete delamination within arc-shaped area23.

The power of the laser coding equipment and the duration of the pulsedbeam on the moving workpiece are readily adjusted to produce the desiredamount of heat within adhesive layer 7 in order to create the desiredpattern of delamination. Generally laser beam power is varied dependingon the thickness of the laminate being worked. Use of laser beams havinga delivered power of about 20to 90 watts have proven useful in thisinvention. Radiant energy wavelengths of from about 9.4 to 10.6 micronshave been successfully employed. Duration of the pulsed beam of from 15to 30 microseconds is typical for use in this invention. Althoughprimarily directed to forming a continuous line of weakness in amultilayer laminate, U.S. Pat. No. 3,790,744 discloses the use of alaser beam to preferentially vaporize at least one layer of a laminatewhich is not the most proximate layer in relation to the laser. Theteachings of this patent are hereby incorporated by reference.

In order to precisely register areas of removed polyester film, asdepicted in FIG. 1-3 as area 2 and in FIG. 4 as area 22 with the areasof delamination 9 and 23, it is desirable that laser energy also beutilized to remove the polyester film (and adjacent ink and adhesivelayers). Typically the power level of the laser used to vaporize thepolyester layer 3 will be greater than that used to create theaforementioned areas of delamination. The application of laser energy toboth the inner surface and the outer surface of the laminated ispreferably done at the same instant.

Having thus described the invention, what is claimed is:
 1. In abeverage pouch made of a multi-layer laminate comprising aheat-sealable, plastic inner layer, which has a relatively lowerabsorption coefficient for laser radiant energy, adhered to the innerface of a metal foil layer by means of an adhesive layer, which has arelatively higher absorption coefficient for laser radiant energy, saidpouch designed to be accessed by a straw that pierces the pouch at adesignated area, characterized in that the pouch has one or more areasof delamination between the plastic inner layer and the metal foil layerwithin the designated straw piercing area in order to facilitate piecingof the multi-layer laminate by the straw.
 2. The beverage pouch of claim1 wherein the areas of delamination results from vaporization of theadhesive.
 3. The beverage pouch of claim 2 wherein, within the areas ofdelamination, a portion of the plastic inner layer adjacent the adhesiveis also vaporized.
 4. The beverage pouch of claim 2 wherein there arespaced-apart areas of delamination.
 5. The beverage pouch of claim 2wherein the area of delamination is arc-shaped.
 6. Method of treatingweb material for use in making beverage pouches designed to be accessedby a straw at a designated straw piercing area, said material being alaminate comprised of a heat-sealable, plastic inner layer, which has arelatively lower coefficient of absorption for laser radiant energy,adhered to the inner face of a metal foil layer by an adhesive layer,which has a relatively higher coefficient of absorption for laserradiant energy, wherein the improvement comprises the steps of:supplying laser energy to the inner face of the laminate within thestraw piercing area such that one or more areas of delamination arecreated between the foil layer and the heat-sealable plastic layer; andfabricating a pouch using said web material.
 7. The method of claim 6wherein areas of delamination are spaced-apart.
 8. The method of claim 6wherein the area of delamination is arc-shaped.
 9. The method of claim 6wherein the laminate includes an outer polyester layer adhered to theouter surface of the metal foil layer by an adhesive layer and thepolyester layer and the adjacent adhesive layer are removed within thestraw piercing area by application of laser energy.